Concrete construction with control joint protective strip

ABSTRACT

A concrete construction includes a formed concrete slab having at least one control joint formed into a surface of the slab to control the location of stress cracks as the slab cures. A control joint protective strip is removably received in the control joint and has a head portion which overlays upper edges of the control joint. The control joint protective strip further includes a stem portion which is configured to engage frictionally interior side walls of the control joint when the stem portion is inserted into the control joint.

FIELD OF THE INVENTION

[0001] The present invention pertains to concrete building materials, and more particularly to a concrete construction having one or more crack control/expansion joints and having a crack control/expansion joint protective strip.

BACKGROUND OF THE INVENTION

[0002] Concrete is often used as a building material in the construction of commercial buildings and other structures. It is common to form individual concrete wall sections by pouring concrete into forms which have been arranged on a horizontal surface, such as a slab of concrete forming the floor of a building. When the concrete has cured, the wall sections are lifted, or tilted to a vertical orientation to form the walls of the building. An inherent characteristic of concrete is that it will shrink as it cures, due to the loss of moisture during the curing process. Shrinkage of the concrete creates internal stresses which, if not addressed in the formation of the concrete slab, will cause random stress cracks to develop throughout the concrete slab. Therefore, a common practice in the formation of concrete slabs is to control the location of shrinkage cracks by forming expansion control joints which, if properly formed, will define where stress cracks develop in the curing concrete slab. Generally, control joints are formed by saw-cutting a relatively narrow channel in one or more selected locations along a poured concrete slab. The cut is preferably made while the concrete is still “green” and as soon after pouring when the concrete will support the weight of persons performing the cutting.

[0003] One drawback of control joints, as described above, is that uncured edges of the control joint are susceptible to damage at the upper edges by personnel or vehicular traffic over the joint prior to cure, whereby edges of the saw-cut joint may be broken. This type of damage to the control joint is known as spalling. Another problem is that control joints are susceptible to the accumulation of unwanted debris in the joint. Such debris must be removed prior to filling the control joint with an appropriate joint sealer.

[0004] As mentioned above, wall sections are commonly formed atop the floor slab. Once the slab has sufficiently cured and control joints have been cut, forms for the wall sections are assembled on the slab, a release agent is applied, and concrete is poured into the forms.

[0005] One drawback of forming the wall sections on the floor slab, as described above, is that the control joints in the floor slab become filled with concrete used to form the wall sections. When the wall sections are eventually raised, the sides of the walls have protruding ridges where the concrete entered the control joints. These ridges must be ground flush with the surface of the sides of the walls. The additional effort required to patch damaged control joints, remove unwanted debris from control joints, and to grind off protruding ridges of formed wall sections contribute to the expense and time required to construct a building from concrete materials.

[0006] There is thus a need for a concrete construction which overcomes the drawbacks of the prior art, such as those described above.

SUMMARY OF THE INVENTION

[0007] The present invention provides a concrete construction for use in erecting buildings and other structures and which provides concrete wall sections having a clean appearance and which do not require subsequent grinding or patching finishing steps. In an exemplary embodiment, the concrete construction includes a concrete section, or slab which has at least one control joint formed into a surface of the slab. The concrete section further includes a control joint protective strip which is removably inserted into the control joint to protect the edges of the control joint while the concrete slab cures and to prevent the accumulation of unwanted debris within the control joint. Advantageously, the control joint protective strip prevents unwanted spalling of the corner edges of the control joint due to human or vehicular traffic over the slab.

[0008] The control joint protective strip is an elongate member having a head portion and an adjoining stem portion. The head portion overlies the upper edges of the control joint when the protective strip is installed to the concrete construction. The stem portion extends from the head portion and is configured to engage frictionally side walls of the control joint. In one exemplary embodiment, the stem portion of the control joint protective strip includes one or more flanges which are configured to engage the side walls of the control joint to retain the protective strip therein. In another exemplary embodiment, the stem portion itself is shaped to engage the side walls of the control joint. For example, the stem portion may have an arcuate shaped section or an angled section which engages the side walls of the control joint. In yet another exemplary embodiment, the stem portion has a bulbous shape which engages the side walls of the control joint.

[0009] The invention also comprises a method of forming a concrete construction including the steps of forming a first concrete section, forming a control joint in the concrete section, and inserting at least one control joint protective strip in the control joint.

[0010] The features and objectives of the present invention will become more readily apparent from the following Detailed Description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the invention.

[0012]FIG. 1 is a perspective cross-sectional view of an exemplary embodiment of the concrete construction of the present invention;

[0013] FIGS. 2A-2J depict various exemplary cross-sectional shapes of the control joint protective strip of the present invention;

[0014]FIG. 3 depicts the exemplary concrete construction of FIG. 1, with a wall section formed on an upper surface; and

[0015]FIG. 4 depicts the concrete construction and wall section of FIG. 3, with the wall section separated and the reveal patched with filler.

DETAILED DESCRIPTION

[0016] Referring to FIG. 1, there is shown an exemplary embodiment of a concrete construction 10 including a control joint protective strip 12. The concrete construction 10 includes a concrete section, or slab 14 in which a control joint 16 has been formed to control the development of stress cracks in the slab 14. While a single control joint 16 is depicted, it is understood that more than one control joint 16 may be formed in a given concrete slab 14 to control the location of stress cracks as may be required. In the exemplary embodiment, the control joint 16 is depicted as a relatively narrow channel having opposing side walls 18, 20 and upper edges 22, 24 defined on an upper surface 26 of the concrete slab 14. The concrete construction 10 further includes an elongate control joint protective strip 12 which has been removably installed into the control joint 16 of the concrete slab 14. The control joint protective strip 12 includes a head portion 30 which covers the upper edges 22, 24 of the control joint 16, and a stem portion 32 which is received into the control joint 16 to engage frictionally the side walls 18, 20 of the control joint 16. Thus installed, the control joint protective strip 12 protects the upper edges 22, 24 of the control joint 16 from contact with personnel or vehicular traffic passing over the control joint 16. The control joint protective strip 12 also prevents unwanted debris from entering and accumulating in the control joint 16 once the protective strip 12 has been installed.

[0017] Referring to FIGS. 2A-2J, various exemplary configurations of a control joint protective strip 12 a-12 j according to the present invention are depicted in cross-section. FIGS. 2A-2D and FIG. 2J depict exemplary cross-sections of control joint protective strips 12 a-12 d and 12 j having head portions 30, stem portions 32, and one or more flanges 34 extending from the stem portions 32. The flanges 34 extending from the stem portion 32 are configured to engage the side walls 18, 20 of the control joint 16 when the stem portions 32 have been inserted into the control joint 16. FIGS. 2E-2G depict cross-sections of exemplary control joint protective strips 12 e-12 g wherein the stem portions 32 are shaped to engage the side walls 18, 20 of the control joint 16 when the protective strips 12 are installed therein. FIGS. 2E and 2G depict cross-sections wherein the stem portions 32 have an arcuate shape, and FIG. 2F depicts an exemplary cross-section wherein the stem portion 32 has an angled shape configured to engage the side walls 18, 20 of the control joint 16.

[0018]FIGS. 2H and 2I depict cross-sections of exemplary control joint protective strips 12 h, 12 i wherein the stem portions 32 have a generally bulbous configuration to engage the side walls 18, 20 of the control joint. In FIG. 2H, the stem portion 32 comprises opposing arcuate portions joined at a distal end 36 of the protective strip 12 to form the bulbous stem portion 32. FIG. 2I depicts a cross-section similar to that of FIG. 2H, but wherein the opposed arcuate portions of the stem 32 are not connected at their distal ends 36.

[0019] With reference to FIG. 1, a method of forming a concrete construction 10, including a concrete slab 14 and a removable control joint protective strip 12, will now be described. An exemplary concrete construction 10, as described above, may be formed by forming a concrete slab 14, forming at least one control joint 16 in the concrete slab 14, and inserting at least one control joint protective strip 12 into the control joint 16. In general, the concrete slab 14 may be formed by pouring concrete into a form which has been arranged on a horizontal surface, as is known in the art. Once the concrete slab 14 has cured to a degree sufficient to support weight on its upper surface, the control joint 16 is formed, such as by saw cutting along a predetermined path, as is known in the art. The joint protective strip 12 is installed to form the concrete section 10 by inserting the stem portion 32 into the control joint 16 to engage frictionally the side walls 22, 24 thereof.

[0020] Referring to FIGS. 3-4, one or more wall sections 38 may be formed on an upper surface 26 of the concrete construction 10. First, a concrete construction 10 is formed, as described above. After the control joint 16 has been formed and the control joint protective strip 12 has been installed into the control joint 16, forms for the wall sections 38 are arranged on the upper surface 26 and concrete is poured into the forms to create the wall sections 38.

[0021] A release agent 40 is applied to concrete construction 10 to prevent fusion between the concrete construction 10 and wall sections 38 and to facilitate separation once the wall sections 38 have cured. Once the wall sections 38 atop the concrete construction have cured sufficiently, additional wall sections may be formed successively on top of wall sections 38 by arranging forms atop the wall sections 38, coating wall sections 38 with a release agent, and pouring concrete into the forms, as described above. Control joints 16 are not generally formed into the successive wall sections 38, but may be if the size of the wall sections 38 requires control joints 16 to control stress cracks. If control joints 16 are formed in the wall sections 38, they may be provided with control joint protective strips 12 as was described above for the underlying slab 14.

[0022] Advantageously, the control joint protective strip 12 prevents concrete used in the formation of the wall sections 38 from filling the control joints 16 of the slab 14 below. Rather, the head portions 30 of the protective strips 12 form slight indentations, or reveals 42, in the side surfaces of the wall sections 38. These reveals 42 may easily be filled with patching material 44, as depicted in FIG. 4, once the wall sections 38 have cured and have been raised into position to form a wall. Alternatively, the reveals 42 may be left unfilled to provide architectural detail, as may be desired. To this end, the control joint protective strip 12 may include a design, provided in relief, on the head portion 30 to thereby create a desired architectural reveal 42 in a wall section 38 which is formed atop an underlying concrete construction 10 that includes the control joint protective strip 12.

[0023] Advantageously, the reveal 42 formed into the wall section 38, whether filled with patching material or left unfilled as an architectural reveal, eliminates or reduces the need to grind the surface of a wall section to remove undesirable ridges as required when the strip 12 is not used to protect control joint 16.

[0024] After the wall sections have been raised, the protective strip 12 may remain in the control joint 16 to protect the control joint 16. Alternatively, the protective strip 12 may be removed from the control joint 16 and the control joint 16 may be filled with a joint sealer.

[0025] While the present invention has been illustrated by the description of the various embodiments thereof, and while the embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of Applicant's general inventive concept. 

What is claimed is:
 1. A concrete construction comprising: a concrete slab having a control joint formed therein, said control joint having side walls and upper edges; an elongate control joint protective strip, including a head portion and a stem portion; said stem portion being removably received in said control joint in frictional engagement with said side walls thereof; and said head portion overlying said upper edges of said control joint.
 2. The construction of claim 1, wherein said stem portion resiliently engages said side walls of said control joint.
 3. The construction of claim 1, wherein said stem portion is bulbous in configuration.
 4. The construction of claim 3, wherein said bulbous stem portion comprises opposed arcuate portions.
 5. The construction of claim 1, wherein said stem portion includes at least one flange extending in a direction away from said stem portion.
 6. The construction of claim 5, wherein said flange is formed integrally with said stem portion.
 7. The construction of claim 1, wherein said stem portion has an angled cross section shaped to engage said side walls of said control joint.
 8. The construction of claim 1, wherein said stem portion has an arcuate cross section shaped to engage said side walls of said control joint.
 9. The construction of claim 1, wherein said head portion includes a design formed into a surface of said head portion.
 10. A method of forming a concrete construction, comprising: forming a concrete slab; forming at least one control joint in the concrete slab; and inserting at least one control joint protective strip in the control joint.
 11. The method of claim 10, further comprising: forming at least one wall section atop the slab.
 12. The method of claim 11, further comprising: forming a reveal in the wall section corresponding to the location of the control joint on the slab.
 13. The method of claim 12, wherein the control joint protective strip has a design formed into a head portion of the strip and the step of forming a reveal in the wall section provides an architectural reveal corresponding to the design.
 14. A concrete construction comprising: a concrete slab; a plurality of concrete wall sections positioned on said slab in stacked, overlying relationship to each other; said slab having at least one elongated control joint formed adjacent an upper surface thereof; said control joint comprising a groove extending downwardly from said upper surface of said slab for a depth less than the thickness of the slab within which it is formed; said control joint having opposed, spaced side walls extending downwardly away from said upper surface of said slab and defining with said upper surface pairs of opposed upper edges; a protective strip associated with said control joint; said protective strip comprising a head portion and a stem portion; said stem portion being removably received within said control joint and frictionally engaging said side walls thereof; said head portion overlying said control joint with an undersurface of said head portion disposed proximate said upper edges of said control joint; whereby said control joint is maintained free of debris and concrete from overlying slabs and said side edges are protected from spalling.
 15. A method of forming a concrete construction comprising: casting a first concrete slab; cutting a control joint in an upper surface thereof extending downwardly away from said upper surface for a depth less than the thickness of said slab and thereby defining opposed, spaced side walls and opposed upper edges at the juncture of said side walls and said upper surface; providing an elongated control joint protective strip having a head portion and a stem portion formed integrally therewith and projecting substantially normally therefrom; inserting said stem portion of said control joint protective strip into said control joint in frictional engagement with said side walls thereof and with said head portion overlying said upper edges of said control joint; and thereafter casting an additional concrete slab on said upper surface of said first concrete slab. 